Subjects -> METEOROLOGY (Total: 106 journals)
 Showing 1 - 36 of 36 Journals sorted alphabetically Acta Meteorologica Sinica       (Followers: 4) Advances in Atmospheric Sciences       (Followers: 43) Advances in Climate Change Research       (Followers: 59) Advances in Meteorology       (Followers: 23) Advances in Statistical Climatology, Meteorology and Oceanography       (Followers: 11) Aeolian Research       (Followers: 7) Agricultural and Forest Meteorology       (Followers: 20) American Journal of Climate Change       (Followers: 41) Atmósfera       (Followers: 2) Atmosphere       (Followers: 32) Atmosphere-Ocean       (Followers: 15) Atmospheric and Oceanic Science Letters       (Followers: 9) Atmospheric Chemistry and Physics (ACP)       (Followers: 43) Atmospheric Chemistry and Physics Discussions (ACPD)       (Followers: 15) Atmospheric Environment       (Followers: 72) Atmospheric Environment : X       (Followers: 3) Atmospheric Research       (Followers: 72) Atmospheric Science Letters       (Followers: 39) Boundary-Layer Meteorology       (Followers: 29) Bulletin of Atmospheric Science and Technology       (Followers: 5) Bulletin of the American Meteorological Society       (Followers: 62) Carbon Balance and Management       (Followers: 6) Ciencia, Ambiente y Clima       (Followers: 1) Climate       (Followers: 6) Climate and Energy       (Followers: 8) Climate Change Economics       (Followers: 50) Climate Change Responses       (Followers: 27) Climate Dynamics       (Followers: 44) Climate Law       (Followers: 6) Climate of the Past (CP)       (Followers: 7) Climate of the Past Discussions (CPD)       (Followers: 1) Climate Policy       (Followers: 53) Climate Research       (Followers: 8) Climate Resilience and Sustainability       (Followers: 26) Climate Risk Management       (Followers: 12) Climate Services       (Followers: 4) Climatic Change       (Followers: 71) Current Climate Change Reports       (Followers: 22) Dynamics and Statistics of the Climate System       (Followers: 6) Dynamics of Atmospheres and Oceans       (Followers: 18) Earth Perspectives - Transdisciplinarity Enabled       (Followers: 1) Economics of Disasters and Climate Change       (Followers: 16) Energy & Environment       (Followers: 26) Environmental and Climate Technologies       (Followers: 3) Environmental Dynamics and Global Climate Change       (Followers: 24) Frontiers in Climate       (Followers: 4) GeoHazards       (Followers: 2) Global Meteorology       (Followers: 17) International Journal of Atmospheric Sciences       (Followers: 24) International Journal of Biometeorology       (Followers: 3) International Journal of Climate Change Strategies and Management       (Followers: 32) International Journal of Climatology       (Followers: 28) International Journal of Environment and Climate Change       (Followers: 24) International Journal of Image and Data Fusion       (Followers: 3) Journal of Agricultural Meteorology Journal of Applied Meteorology and Climatology       (Followers: 40) Journal of Atmospheric and Oceanic Technology       (Followers: 33) Journal of Atmospheric and Solar-Terrestrial Physics       (Followers: 159) Journal of Atmospheric Chemistry       (Followers: 23) Journal of Climate       (Followers: 55) Journal of Climate Change       (Followers: 25) Journal of Climate Change and Health       (Followers: 6) Journal of Climatology       (Followers: 3) Journal of Economic Literature       (Followers: 19) Journal of Hydrology and Meteorology       (Followers: 39) Journal of Hydrometeorology       (Followers: 9) Journal of Integrative Environmental Sciences       (Followers: 4) Journal of Meteorological Research       (Followers: 2) Journal of Meteorology and Climate Science       (Followers: 17) Journal of Space Weather and Space Climate       (Followers: 30) Journal of the Atmospheric Sciences       (Followers: 79) Journal of the Meteorological Society of Japan       (Followers: 7) Journal of Weather Modification       (Followers: 3) Mediterranean Marine Science       (Followers: 2) Meteorologica       (Followers: 2) Meteorological Applications       (Followers: 4) Meteorological Monographs       (Followers: 1) Meteorologische Zeitschrift       (Followers: 4) Meteorology and Atmospheric Physics       (Followers: 28) Mètode Science Studies Journal : Annual Review Michigan Journal of Sustainability       (Followers: 1) Modeling Earth Systems and Environment       (Followers: 1) Monthly Notices of the Royal Astronomical Society       (Followers: 13) Monthly Weather Review       (Followers: 29) Nature Climate Change       (Followers: 150) Nature Reports Climate Change       (Followers: 39) Nīvār       (Followers: 1) npj Climate and Atmospheric Science       (Followers: 3) Open Atmospheric Science Journal       (Followers: 4) Open Journal of Modern Hydrology       (Followers: 5) Oxford Open Climate Change       (Followers: 5) Revista Iberoamericana de Bioeconomía y Cambio Climático       (Followers: 1) Russian Meteorology and Hydrology       (Followers: 3) Space Weather       (Followers: 27) Studia Geophysica et Geodaetica       (Followers: 1) Tellus A       (Followers: 21) Tellus B       (Followers: 20) The Cryosphere (TC)       (Followers: 8) The Quarterly Journal of the Royal Meteorological Society       (Followers: 31) Theoretical and Applied Climatology       (Followers: 13) Tropical Cyclone Research and Review       (Followers: 1) Urban Climate       (Followers: 4) Weather and Climate Dynamics       (Followers: 1) Weather and Climate Extremes       (Followers: 17) Weather and Forecasting       (Followers: 42) Weatherwise       (Followers: 18) 气候与环境研究       (Followers: 2)
Similar Journals
 Journal of Meteorological ResearchNumber of Followers: 2      Subscription journal ISSN (Print) 2095-6037 - ISSN (Online) 2198-0934 Published by Springer-Verlag  [2469 journals]
• Estimation of Terrestrial Net Primary Productivity in China from
Fengyun-3D Satellite Data

Abstract: Abstract Currently, the satellite data used to estimate terrestrial net primary productivity (NPP) in China are predominantly from foreign satellites, and very few studies have based their estimates on data from China’s Fengyun satellites. Moreover, despite their importance, the influence of land cover types and the normalized difference vegetation index (NDVI) on NPP estimation has not been clarified. This study employs the Carnegie—Ames—Stanford approach (CASA) model to compute the fraction of absorbed photosynthetically active radiation and the maximum light use efficiency suitable for the main vegetation types in China in accordance with the finer resolution observation and monitoring-global land cover (FROM-GLC) classification product. Then, the NPP is estimated from the Fengyun-3D (FY-3D) data and compared with the Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product. The FY-3D NPP is also validated with existing research results and historical field-measured NPP data. In addition, the effects of land cover types and the NDVI on NPP estimation are analyzed. The results show that the CASA model and the FY-3D satellite data estimate an average NPP of 441.2 g C m−2 yr−1 in 2019 for China’s terrestrial vegetation, while the total NPP is 3.19 Pg C yr−1. Compared with the MODIS NPP, the FY-3D NPP is overestimated in areas of low vegetation productivity and is underestimated in high-productivity areas. These discrepancies are largely due to the differences between the FY-3D NDVI and MODIS NDVI. Compared with historical field-measured data, the FY-3D NPP estimation results outperformed the MODIS NPP results, although the deviation between the FY-3D NPP estimate and the in-situ measurement was large and may exceed 20% at the pixel scale. The land cover types and the NDVI significantly affected the spatial distribution of NPP and accounted for NPP deviations of 17.0% and 18.1%, respectively. Additionally, the total deviation resulting from the two factors reached 29.5%. These results show that accurate NDVI products and land cover types are important prerequisites for NPP estimation.
PubDate: 2022-06-01

• Dynamic Trigger and Moisture Source of Two Typical Meiyu Front Rainstorms
Associated with Eastward-Moving Cloud Clusters from the Tibetan Plateau

Abstract: Abstract Eastward-moving cloud clusters from the Tibetan Plateau (TP) often trigger heavy rainfall events in the Yangtze River basin in summer. Forecasting these events in an operational environment remains a challenging task. Here, dynamical diagnosis and a Lagrangian trajectory model are used to analyze the background atmospheric circulation, maintenance mechanism, and moisture transport of two Meiyu front rainstorms (MYFR) during 30 June–2 July 2016 and 17–19 June 2018 associated with eastward-moving cloud clusters from the TP. It is shown that in both cases heavy rainfall is characterized by semi-continuous rainbelts extending from the eastern TP to the Yangtze River valleys with eastward-spreading convective clouds weakening and strengthening alternately from the eastern TP to downstream regions. Following the track of positive water vapor advection, centers of positive vorticity propagate downstream through the Sichuan basin. The baroclinic thermodynamic—dynamical interaction and the barotropic non-equilibrium force work against each other in the development of the MYFR. Specifically, during the early stage of precipitation development, the barotropic non-equilibrium force dominates, while during the period of heavy precipitation the baroclinic thermodynamic—dynamical interaction dominates. The convergence associated with the baroclinic thermodynamic—dynamical interaction guarantees the persistence of heavy precipitation. Compared to the climate mean state (1988–2018), both MYFR events associated with eastward-moving cloud clusters from the eastern TP are characterized by increased moisture transport from the southwest. One of the major paths of moisture transport in both cases is along the south side of the TP, directly connected to the eastward movement of cloud clusters.
PubDate: 2022-06-01

• On the Increased Precipitation Recycling by Large-Scale Irrigation over
the Haihe Plain

Abstract: Abstract Irrigation not only plays an important role in global food security, but it also affects aspects of the regional climate, including precipitation. In this study, we proposed a simple and convenient method to quantify the contribution of large-scale irrigation to precipitation by distinguishing the amount of evaporation generated by irrigation from local evaporation based on the precipitation recycling method. A case study was presented to show the increased precipitation recycling ratio and the contribution of irrigation to precipitation during the main irrigation period in the Haihe Plain from 1961 to 2016. We found that the average precipitation recycling rates in the Haihe Plain are 8.32%, 9.74%, and 10.36% in April, May, and June, respectively. The contribution rates of irrigation to precipitation in the Haihe Plain are 3.76%, 5.12%, and 2.29% in April, May, and June, respectively. The total contribution of irrigation to precipitation during the main irrigation period is 3.77 mm; the respective contributions in April, May, and June are 0.72, 1.70, and 1.35 mm. The contribution of irrigation to local precipitation is relatively small as the inflow of atmospheric moisture during the irrigation period is still the main factor affecting local precipitation. Nevertheless, this part of the precipitation during the irrigation period alleviates the water shortage in the Haihe Plain to some extent.
PubDate: 2022-06-01

• Forty Years of Air Temperature Change over Iran Reveals Linear and
Nonlinear Warming

Abstract: Abstract Spatiotemporal analysis of long-term changes in air temperature is of prime importance for climate change research and the development of effective mitigation and adaptation strategies. Although there are considerable studies on air temperature change across the globe, most of them have been on linear trends and time series analysis of nonlinear trends have not received enough attention. Here, spatiotemporal patterns of monthly and annual mean (Tmean), maximum (Tmax), and minimum (Tmin) air temperature at 47 synoptic stations across climate zones in Iran for a 40-yr period (1978–2017) are analyzed. A polynomial fitting scheme (Polytrend) is used to both monthly and annual air temperature data to detect trends and classify them into linear and nonlinear (quadratic and cubic) categories. The significant (non-significant) trends in Tmean, Tmax, and Tmin across all climate zones are 41.1% (58.9%), 34.1% (65.9%), and 46% (54%), respectively. The highest magnitude of increasing trends is observed in the annual Tmin (0.47°C decade−1) and the lowest magnitude is for the annual Tmax (0.4°C decade−1). Across the country, increasing trends $$(\bar x = 37.2\% )$$ have higher spatial coverage than the decreasing trends $$(\bar x = 3.2\% )$$ . Warming trends in Tmean (65.3%) and Tmin (73.1%) are mainly observed in humid climate zone while warming trends in Tmax are in semi-arid (43.9%) and arid (34.1%) climates. Linear change with a positive trend is predominant in all Tmean (56.7%), Tmax (67.8%), and Tmin (71.2%) and for both monthly and annual data. Further, the linear trends have the highest warming rate in annual Tmin (0.83°C decade−1) and Tmean (0.46°C decade−1) whereas the nonlinear trends have the highest warming rate in annual Tmax (0.52°C decade−1). The linear trend type is predominant across the country especially in humid climate zones whereas the nonlinear trends (quadratic and cubic) are mainly observed in the arid climate zones. This study highlights nonlinear changes and spatiotemporal trends in air temperature in Iran and contributes to a growing body of climate change literature that is necessary for the development of effective mitigation and adaptation strategies in the Middle East.
PubDate: 2022-06-01

• Three-Dimensional Urban Thermal Effect across a Large City Cluster during
an Extreme Heat Wave: Observational Analysis

Abstract: Abstract Given extensive and rapid urbanization globally, assessing regional urban thermal effects (UTE) in both canopy and boundary layers under extreme weather/climate conditions is of significant interest. Rapid population and economic growth in the Yangtze River Delta (YRD) have made it one of the largest city clusters in China. Here, we explore the three-dimensional (3D) UTE in the YRD using multi-source observations from high-resolution automatic weather stations, radiosondes, and eddy covariance sensors during the record-setting heat wave (HW) of July–August 2013. It is found that the regional canopy layer UTE is up to 0.6–1.2°C, and the nocturnal UTE (0.7–1.6°C) is larger than daytime UTE (0.2–0.5°C) during the HW. The regional canopy layer UTE is enhanced and expanded northwards, with some rural sites contaminated by the urban influences, especially at night. In the boundary layer, the strengthened regional UTE extends vertically to at least 925 hPa (∼750 m) during this HW. The strengthened 3D UTE in the YRD is associated with an enlarged Bowen ratio difference between urban and non-urban areas. These findings about the 3D UTE are beneficial for better understanding of the thermal environment of large city clusters under HW and for more appropriate adaption and mitigation strategies.
PubDate: 2022-06-01

• Variations of Raindrop Size Distribution and Radar Retrieval in Outer
Rainbands of Typhoon Mangkhut (2018)

Abstract: Abstract The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated. The observations by three two-dimensional video disdrometers deployed in central Guangdong Province were analyzed concurrently. It was found that the radial distribution of the median volume diameter (D0) and normalized intercept parameter (Nw) varied in different stages, and that raindrops smaller than 3.0 mm contributed more than 99% of the total precipitation. Considering the characteristics of precipitation in the typhoon outer rainband, a modified stratiform rain (SR)—convective rain (CR) separator line is proposed based on D0 and Nw scatterplots. Meanwhile, an “S—C likelihood index” is introduced, which was used to classify three rain types (SR, CR, and mixed rain). The CR results were highly consistent with those of the improved typhoon precipitation classification method based on rain rate. By calculating effectively the radar reflectivity factor (Ze) in the Ku and Ka bands, D0—Ze and Nw—D0 empirical relations were thereby derived for improving the accuracy of rainfall retrieval. Among the four quantitative precipitation estimators using S-band dual-polarimetric radar parameters simulated by the T-matrix method, the estimator that adopted the specific differential phase and differential reflectivity was found to be the most effective for both SR and CR.
PubDate: 2022-06-01

• Present-Day PM2.5 over Asia: Simulation and Uncertainty in CMIP6 ESMs

Abstract: Abstract This study assesses the ability of 10 Earth System Models (ESMs) that participated in the Coupled Model Inter-comparison Project Phase 6 (CMIP6) to reproduce the present-day inhalable particles with diameters less than 2.5 micrometers (PM2.5) over Asia and discusses the uncertainty. PM2.5 accounts for more than 30% of the surface total aerosol (fine and coarse) concentration over Asia, except for central Asia. The simulated spatial distributions of PM2.5 and its components, averaged from 2005 to 2020, are consistent with the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) reanalysis. They are characterized by the high PM2.5 concentrations in eastern China and northern India where anthropogenic components such as sulfate and organic aerosol dominate, and in northwestern China where the mineral dust in PM2.5 fine particles (PM2.5DU) dominates. The present-day multi-model mean (MME) PM2.5 concentrations slightly underestimate ground-based observations in the same period of 2014–2019, although observations are affected by the limited coverage of observation sites and the urban areas. Those model biases partly come from other aerosols (such as nitrate and ammonium) not involved in our analyses, and also are contributed by large uncertainty in PM2.5 simulations on local scale among ESMs. The model uncertainties over East Asia are mainly attributed to sulfate and PM2.5DU; over South Asia, they are attributed to sulfate, organic aerosol, and PM2.5DU; over Southeast Asia, they are attributed to sea salt in PM2.5 fine particles (PM2.5SS); and over central Asia, they are attributed to PM2.5DU. They are mainly caused by the different representations of aerosols within individual ESMs including the representation of aerosol size distributions, dynamic transport, and physical and chemistry mechanisms.
PubDate: 2022-06-01

• Cloud Water Resource in North China in 2017 Simulated by the CMA-CPEFS
Cloud Resolving Model: Validation and Quantification

Abstract: Abstract Based on the concept of cloud water resource (CWR) and the cloud microphysical scheme developed by the Chinese Academy of Meteorological Sciences (CAMS), a coupled mesoscale and cloud-resolving model system is developed in the study for CWR numerical quantification (CWR-NQ) in North China for 2017. The results show that (1) the model system is stable and capable for performing 1-yr continuous simulation with a water budget error of less than 0.2%, which indicates a good water balance. (2) Compared with the observational data, it is confirmed that the simulating capability of the CWR-NQ approach is decent for the spatial distribution of yearly cumulative precipitation, daily precipitation intensity, yearly average spatial distribution of water vapor. (3) Compared with the CWR diagnostic quantification (CWR-DQ), the results from the CWR-NQ differ mainly in cloud condensation and cloud evaporation. However, the deviation of the net condensation (condensation minus evaporation) between the two methods is less than 1%. For other composition variables, such as water vapor advection, surface evaporation, precipitation, cloud condensation, and total atmospheric water substances, the relative differences between the CWR-NQ and the CWR-DQ are less than 5%. (4) The spatiotemporal features of the CWR in North China are also studied. The positive correlation between water vapor convergence and precipitation on monthly and seasonal scales, and the lag of precipitation relative to water vapor convergence on hourly and daily scales are analyzed in detail, indicating the significance of the state term on hourly and daily scales. The effects of different spatial scales on the state term, advection term, source—sink term, and total amount are analyzed. It is shown that the advective term varies greatly at different spatiotemporal scales, which leads to differences at different spatiotemporal scales in CWR and related characteristic quantities.
PubDate: 2022-06-01

• Evaluation of Reprocessed Fengyun-3B Global Outgoing Longwave Radiation
Data: Comparison with CERES OLR

Abstract: Abstract Outgoing longwave radiation (OLR) at the top of the atmosphere (TOA) is a key parameter for understanding and interpreting the relationship between clouds, radiation, and climate interactions. It has been one of the operational products of the Fengyun (FY) meteorological satellites. OLR accuracy has gradually improved with advancements in satellite payload performance and the OLR retrieval algorithm. Supported by the National Key R&D Program Retrospective Calibration of Historical Chinese Earth Observation Satellite data (Richceos) project, a long-term OLR climate data record (CDR) was reprocessed based on the recalibrated Level 1 data of FY series satellites using the latest OLR retrieval algorithm. In this study, Fengyun-3B (FY-3B)’s reprocessed global OLR data from 2010 to 2018 were evaluated by using the Clouds and the Earth’s Radiant Energy System (CERES) global daily OLR data. The results showed that there was a high consistency between the FY-3B instantaneous OLR and CERES Single Scanner Footprint (SSF) OLR. Globally, between the two CDR datasets, the correlation coefficient reached 0.98, and the root-mean-square error (RMSE) was approximately 8–9 W m−2. The bias mainly came from the edge regions of the satellite orbit, which may be related to the satellite zenith angle and cloud cover distribution. It was shown that the long-term FY-3B OLR had temporal stability compared to CERES OLR long-term data. In terms of spatial distribution, the mean deviations showed zonal and seasonal characteristics, although seasonal fluctuations were observed in the differences between the two datasets. Effects of FY-3B OLR application to the South China Sea monsoon region and ENSO were demonstrated and analyzed, and the results showed that the seasonal deviation of FY-3B’s OLR comes mainly from the retrieval algorithm. However, it has little effect on the analysis of climate events.
PubDate: 2022-06-01

• CMIP6 Projections of the “Warming-Wetting” Trend in Northwest China
and Related Extreme Events Based on Observational Constraints

Abstract: Abstract This study presents the improved future projections of the climate “warming—wetting” trend and climate extremes with different return periods in Northwest China at different global warming levels. The projections are based on the Coupled Model Intercomparison Project phase 6 (CMIP6) simulations constrained by the high-resolution observation dataset using the equidistant cumulative distribution functions (EDCDF) method. The results indicate that the climate will experience continuous warming and wetting as reflected by average temperature and total precipitation over Northwest China, especially under the scenario of the shared socioeconomic pathway 5—representative concentration pathway 8.5 (SSP5–8.5). Most parts of Northwest China will continue to warm in the future more than global average. Spatially, areas with prominent “warming—wetting” trends will be mainly distributed in western Northwest China. It is worth noting that extreme heat and precipitation events will also increase with the climate warming and wetting over Northwest China. Moreover, frequencies of rarer extreme events will increase more apparently than weaker extreme events and frequency increase of extreme heat events responds to global warming faster than that of extreme precipitation events. Limiting global warming within 2°C relative to 1850–1900 would slowdown the increase in extreme heat events and considerably suppress the increase in frequencies of extreme precipitation events, especially the rare (i.e., 50-yr) extreme events.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1157-8

• Sensitivity of Lake-Effect Convection to the Lake Surface Temperature over
Poyang Lake in China

Abstract: Abstract In this study, high-resolution weather research and forecasting (WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake (PL) to the change of lake surface temperature (LST). A control experiment (CTR) with climate mean LST (303 K) is compared with six sensitivity experiments (CTR−1/2/3K and CTR+1/2/3K) in which the LSTs are set based on the mean LST difference of 6 K between the maximum and minimum. The results show that the CTR experiment reasonably reproduces the lake-effect convection, and the lake-effect convection in sensitivity experiments is significantly influenced by the LST. With the increase of LST, the initiation time of the lake-effect convection is advanced gradually, while the initiation location moves PL from its shore. The lake-effect convection strengthens (weakens) in the increase-temperature CTR+1/2/3K (decrease-temperature CTR−1/2/3K) experiments, but the lake-effect convection does not monotonically strengthen with the LST, for the strongest one occurring in the CTR+1K experiment. The corresponding diagnostic analysis shows that the upward sensible heat flux and latent heat flux over PL increase with the LST, resulting in the enhancement of the lake-land breeze and the enlargement of the convective available potential energy (CAPE). This is the main reason for the changes in the initiation time and location, as well as the intensity of lake-effect convection in different experiments. In addition, the non-monotonous variation of the level of free convection, which is mainly induced by the non-monotonous variation of the lifting condensation level, is responsible for the non-monotonous variation of the lake-effect convection intensity with the LST.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1142-2

• Diagnostic Quantification of the Cloud Water Resource in China during
2000–2019

Abstract: Abstract By using the diagnostic quantification method for cloud water resource (CWR), the three-dimensional (3D) cloud fields of 1° × 1° resolution during 2000–2019 in China are firstly obtained based on the NCEP reanalysis data and related satellite data. Then, combined with the Global Precipitation Climatology Project (GPCP) products, a 1° × 1° gridded CWR dataset of China in recent 20 years is established. On this basis, the monthly and annual CWR and related variables in China and its six weather modification operation sub-regions are obtained, and the CWR characteristics in different regions are analyzed finally. The results show that in the past 20 years, the annual total amount of atmospheric hydrometeors (GMh) and water vapor (GMv) in the Chinese mainland are about 838.1 and 3835.9 mm, respectively. After deducting the annual mean precipitation of China (Ps, 661.7 mm), the annual CWR is about 176.4 mm. Among the six sub-regions, the southeast region has the largest amount of cloud condensation (Cvh) and precipitation, leading to the largest GMh and CWR there. In contrast, the annual Ps, GMh, and CWR are all the least in the northwest region. Furthermore, the monthly and interannual variation trends of Ps, Cvh, and GMh in different regions are identical, and the evolution characteristics of CWR are also consistent with the hydrometeor inflow (Qhi). For the north, northwest, and northeast regions, in spring and autumn the precipitation efficiency of hydrometeors (PEh) is not high (20%–60%), the renewal time of hydrometeors (RTh) is relatively long (5–25 h), and GMh is relatively high. Therefore, there is great potential for the development of CWR through artificial precipitation enhancement (APE). For the central region, spring, autumn, and winter are suitable seasons for CWR development. For the southeast and southwest regions, Ps and PEh in summer are so high that the development of CWR should be avoided. For different spatial scales, there are significant differences in the characteristics of CWR.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1111-9

• Reprocessing 12-yr Microwave Humidity Sounder Historical Data of Fengyun-3
Satellites

Abstract: Abstract Atmospheric water vapor is an essential climate variable (ECV) with extensive spatial and temporal variations. Microwave humidity observations from meteorological satellites provide important information for climate system variables, including atmospheric water vapor and precipitable water, and assimilation in numerical weather prediction (NWP) and reanalysis. As one of the payloads onboard China’s second-generation polar-orbiting operational meteorological Fengyun-3 (FY-3) satellites, the Microwave Humidity Sounder (MWHS) has been continuously observing the global humidity since 2008. The reprocessing of historical FY-3 MWHS data is documented in detail in this study. After calibrating and correcting the data, the quality of the reprocessed dataset is evaluated and the improvement is shown in this study. The results suggest that MWHS observations bias is reduced to approximately 0.8 K, compared with METOP-A Microwave Humidity Sounder (MHS). The temporal variability of MWHS is highly correlated with the instrument temperature. After reprocessing, the scene temperature dependency is mitigated for all 183 GHz channels, and the consistency and stability between FY-3A/B/C are also improved.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1110-x

• Factors Influencing Diurnal Variations of Cloud and Precipitation in the
Yushu Area of the Tibetan Plateau

Abstract: Abstract Using the cloud radar, ground observations, and ECMWF Reanalysis v5 (ERA5) data, we investigate the factors influencing nighttime precipitation during summer in the Yushu area of the Tibetan Plateau (TP). The cloud top height (CTH), cloud base height (CBH), and liquid water content (LWC) are compared between non-precipitation and precipitation days. The results show that the average CTH on precipitation days in Yushu is below 10 km above ground level (AGL) in the daytime, whereas it exceeds 10 km AGL at night, with the maximum at 2300 BT (Beijing Time). The CBH is in-phase with the dewpoint spread. The precipitation intensity and CTH are in-phase with the LWC. The hourly averaged precipitation intensity and convective available potential energy in ERA5 reach their maximums at 2100 BT, which is 3 h ahead of their observed counterparts. There is descending motion in the mid day on non-precipitation days, whereas there is ascending motion at night on precipitation days. In addition, the horizontal wind direction in the lower level (below 5000 m) shows clockwise rotation from morning to night. Wind shear occurs in the mid level of the atmosphere, accompanied by a subtropical westerly jet in the upper level. The difference in horizontal wind speed between 200 and 500 hPa is positively related to the LWC, thereby contributing to the formation of upper-level cloud.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1167-6

• Deep Learning for Seasonal Precipitation Prediction over China

Abstract: Abstract Despite significant progress having been made in recent years, the forecast skill for seasonal precipitation over China remains limited. In this study, a deep-learning-based statistical prediction model for seasonal precipitation over China was developed. The model was trained to learn the distribution of the seasonal precipitation using simultaneous general circulation data. First, it was pre-trained with the hindcasts of several general circulation models (GCMs), and evaluation of the test set suggested that the pre-trained model could basically reproduce the GCM-predicted precipitation, with the anomaly pattern correlation coefficients (PCCs) greater than 0.80. Then, transfer learning was applied by using ECMWF Reanalysis v5 (ERA5) data and gridded precipitation observational data over China, to further correct the systemic errors in the model. As a result, using general circulation fields from reanalysis as the input, this hybrid model performed reasonably well in simulating the seasonal precipitation over China, with the PCC reaching 0.71. In addition, the results using the circulation fields predicted by GCMs as the input were also assessed. In general, the proposed model improves the PCC over China by 0.10–0.13, as compared to the raw GCM outputs, for lead times of 1–4 months. This deep learning model has been used at the National Climate Center of China Meteorological Administration for the past two years to provide guidance for summer precipitation prediction over China and has performed extremely well.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1174-7

• Fast CO2 Retrieval Using a Semi-Physical Statistical Model for the
High-Resolution Spectrometer on the Fengyun-3D Satellite

Abstract: Abstract China’s Fengyun-3D meteorological satellite launched in December 2016 carries the high-resolution greenhouse-gases absorption spectrometer (GAS) aimed at providing global observations of carbon dioxide (CO2). To date, GAS is one of the few instruments measuring CO2 from the near-infrared spectrum. On orbit, the oxygen (O2) A band suffers a disturbance, and the signal-to-noise ratio (SNR) is significantly lower than the nominal specification. This leads to difficulties in the retrieval of surface pressure and hence a degradation of the retrieval of the column-averaged CO2 dry air mole fraction (XCO2) if a full physics retrieval algorithm is used. Thus, a fast CO2 inverse method, named semi-physical statistical algorithm, was developed to overcome this deficiency. The instrument characteristics, the semi-physical statistical algorithm, and the results of comparison with ground-based measurements over land were introduced in this paper. XCO2 can be obtained from three bands, namely, the O2 A, weak CO2, and strong CO2 bands, with compensation from the Medium Resolution Spectral Imager-2 (MERSI-2) products, ECMWF Reanalysis v5 (ERA-5) data, and Total Carbon Column Observing Network (TCCON) data. The eigenvectors of covariance matrices and the least square fits were used to derive retrieval coefficients and yield cloud-free solutions. In addition to the GAS radiance, some key factors necessary for the accurate estimations of XCO2 were also taken as input information (e.g., air mass, surface pressure, and a priori XCO2). The global GAS XCO2 restricted over land was compared against the simultaneously collocated observations from TCCON. The retrieval algorithm can mitigate the issue caused by the low SNR of the O2 A band to a certain extent. Overall, through site-by-site comparisons, GAS XCO2 agreed well with the average precision (1σ) of 1.52 ppm and bias of −0.007 ppm. The seasonal variation trends of GAS XCO2 can be clearly seen at TCCON sites on the 1-yr timescale.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1149-8

• Upper-Ocean Lateral Heat Transports in the Niño3.4 Region and Their
Connection with ENSO

Abstract: Abstract In the Niño3.4 region (tropical Pacific, 5°S–5°N, 170°–120°W), sea surface temperature (SST) changes are highly correlated with temperature variations in the upper 40-m layer. This study explores the upper-ocean heat budget in the Niño3.4 region using Ocean Reanalysis System 5 (ORAS5) monthly data from 1979 to 2018, with a focus on ocean heat transports at lateral boundaries in the top 40-m layer and their correlation with temperature variations. In the region, there is a well-defined structure of opposite meridional circulation in the upper and lower parts of the thermocline, characterized by divergence in the upper layer above 40 m and convergence in the lower layer. The change of mean temperature in the upper layer is determined by the sum of zonal, meridional, and vertical heat transports, which, however, tend to largely compensate for each other. In general, part of the surface heat flux from the atmosphere to the ocean and the heat transport from the subsurface ocean are transported out of the domain by meridional and zonal currents, leaving only a tiny part to warm or cool the upper ocean. The amplitude of the net surface heat flux effective for the entire 40-m layer of the ocean is weaker than the lateral heat transport. On an interannual timescale, variations of heat transports in both zonal and meridional are positively correlated with temperature anomalies, while the vertical heat transport from the subsurface ocean is negatively correlated. Composite analyses for five El Niño events and five La Niña events also revealed that there is a positive contribution of horizontal transport convergence to temperature anomalies during the evolution of El Niño (warming) and La Niña (cooling), while vertical transport acts against temperature variations.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1175-6

• Comparison between the Roles of Low-Level Jets in Two Heavy Rainfall
Events over South China

Abstract: Abstract Two heavy rainfall events occurred over the Pearl River Delta during 20–22 May 2020: the first was a warm-sector event and the second a frontal event. Based on ERA5 reanalysis data and observations from wind profilers and Doppler weather radars, the structures and roles of low-level jets (LLJs) during these two heavy rainfall events were analyzed. The results show that: (1) South China was affected by a low-level vortex and a low-level shear line during the two processes. The two heavy rainfall events were both associated with a synoptic-system-related low-level jet (SLLJ) and a boundary layer jet (BLJ). The coupling of the convergence at the exit of the BLJ and the divergence at the entrance of the SLLJ produced strong lifting for the warm-sector heavy rainfall, and the strong convergence between the LLJs and northerly winds as the cold front moved southwards was the main lifting reason for the frontal heavy rainfall. (2) The BLJ was the main transport of water vapor during the two processes. The coupling of the BLJ and SLLJ caused the water vapor convergence to be concentrated in the boundary layer during the first process, whereas the strong convergence between the LLJs and northerly winds led to the lower and middle troposphere having strong water vapor convergence during the second process. (3) During the period of these two heavy rainfall events, the lower and middle troposphere remained unstable. Further analysis show that the differences in the intensity, location, and direction between the BLJ and SLLJ resulted in the pseudo-equivalent potential temperature advection in the boundary layer being significantly larger than in the lower and middle troposphere, which compensated for the energy loss caused by heavy rainfall and maintained the convective instability. These findings add to our knowledge on the roles of LLJs in the pre-summer rainfall over South China.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1159-6

• Role of Anthropogenic Climate Change in Autumn Drought Trend over China
from 1961 to 2014

Abstract: Abstract Understanding the impact of anthropogenic climate change on drought is of great significance to the prevention of its adverse effects. Two drought indices, standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI), are used here for the detection and attribution of autumn droughts in China, and for the exploration of the role played by the anthropogenic climate change. SPI is only related to precipitation, but SPEI involves both precipitation and potential evapotranspiration. For their trend’s spatial patterns, the historical simulations (including all forcings, noted as ALL) from 11 models of the Coupled Model Intercomparison Project phase 6, as an ensemble, are able to reproduce their observational counterpart. SPI shows wetting trend in the north of 35°N and drying trend in the south. SPEI shows drying trend in almost whole China. The drying trend in historical simulations ALL is significantly stronger, compared with the counterpart from the accompanying simulations (called NAT) with only natural forcings implemented. This result clearly indicates that anthropogenic climate change plays a dominant role in the enhancement of autumn drought in China. A more rigorous detection work is also performed with the signal’s fingerprint of ALL (and NAT) projected onto the observation and assessed with the background noise from no external-forcing control simulations. The trend pattern signal in ALL is significantly detected in observation for both SPI and SPEI, with a more pronounced signal in SPEI than in SPI, while the signal of NAT is not detected for neither SPI nor SPEI. Finally, extreme droughts (with indices beyond −2) are assessed in terms of probability ratio between ALL and NAT. It is shown that the anthropogenic precipitation change plays a leading role in the south of 35°N, while the anthropogenic temperature change leads in the north.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1178-3

• An Updated Review of Event Attribution Approaches

Abstract: Abstract There have been considerable high-impact extreme events occurring around the world in the context of climate change. Event attribution studies, which seek to quantitatively answer whether and to what extent anthropogenic climate change has altered the characteristics—predominantly the probability and magnitude—of particular events, have been gaining increasing interest within the research community. This paper reviews the latest approaches used in event attribution studies through a new classification into three major categories according to how the event attribution question is framed—namely, the risk-based approach, the storyline approach, and the combined approach. Four approaches in the risk-based framing category and three in the storyline framing category are also reviewed in detail. The advantages and disadvantages of each approach are discussed. Particular attention is paid to the ability, suitability, and applicability of these approaches in attributing extreme events in China, a typical monsoonal region where climate models may not perform well. Most of these approaches are applicable in China, and some are more suitable for analyzing temperature events. There is no right or wrong among these approaches, but different approaches have different framings. The uncertainties in attribution results come from several aspects, including different categories of framing, different conditions in climate model approaches, different models, different definitions of the event, and different observational data used. Clarification of these aspects can help to understand the differences in attribution results from different studies.
PubDate: 2022-04-01
DOI: 10.1007/s13351-022-1192-5

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